Example: I am making a shop where you can buy some digital items. Invoice with new ETH account is generated for every order. When customer pays invoice, order must be marked as completed. To do so I need some kind of notification (like wallet notify in bitcoin) when transaction is received.
I don't want to use any 3rd party service for notification. Application is for learning purposes.
What is the best solution for balance change notification?
Is checking every block for transactions to that account is still best approach?
Maybe Smart Contracts could bring some light?